wow, that's pretty impressive! I remember at Laguna Seca I had started walking down towards the track after one of the morning practices and as I'm walking within 30 to 40 meters of the track I notice something flashing by out of the corner of my eye. I realize it's the electric bikes on the track and I couldn't a damn thing coming from the track. It was pretty incredible at the amount of power they produce for such a quiet sound.
The video doesn't do it justice, you have to hear it in person. Or just go to airport and listen to jet liners take off, because that is EXACTLY what it sounds like. Apparently the Moto czysz bike sounds even cooler.